CN105389268B - Data storage system and operation method thereof - Google Patents

Abstract

A data storage system and its operation method. The data storage system includes a data storage unit, a cache unit and a data access unit. The data access unit is coupled to the data storage unit and the cache unit. When the data access unit receives a data write command from a host, the data access unit is used to reply to the host with a write completion command after a write data in the data write command is stored in the cache unit, the data write command is put into a data write schedule, and the write data is read from the cache unit and written to the data storage unit according to the data write schedule.

Description

Data storage system and method of operation

technical field

The present invention relates to a data storage system and its operation method, and in particular to a data storage system with segment processing data writing instructions and its operation method.

Background technique

At present, mass storage devices on the market can be mainly divided into traditional hard disks (HardDriver disk, HDD) composed of magnetic heads and magnetic disks, and solid state disks (SolidState Disk, SSD) composed of non-volatile memory. Generally speaking, when receiving a data write command from the host, the storage device needs to confirm that the data has been completely written into the main storage unit (disk or non-volatile memory) before replying to the host with a write completion command. The host will send the next command to the storage device after receiving the writing completion command. However, it takes a long time to completely write data into the main storage unit (disk or non-volatile memory), which will affect the overall performance of the computer system. Therefore, how to improve the access speed and security of data at the same time is still an important issue in the design of storage devices. a key point.

Contents of the invention

The present invention provides a data storage system and its operation method, which uses a data access unit to process data writing instructions in segments, so as to improve the data reading and writing efficiency of the data storage system, and can greatly reduce the amount of data loss in the data storage system , to improve the data storage reliability of the data storage system.

The data storage system of the present invention includes a data storage unit, a cache unit and a data access unit. The data access unit is coupled to the data storage unit and the cache unit. When the data access unit receives a data write command from a host, the data access unit is used to store a write data in the data write command in the cache unit and then reply the host with a write completion command, and The data write command is entered into a data write schedule, and the write data is read from the cache unit and written into the data storage unit according to the data write schedule.

In one embodiment of the present invention, the data access unit has a cache data correspondence table and a data writing schedule table, wherein the cache data correspondence table is used to record a data write data stored in the cache unit Corresponding to the address information, the data writing schedule table is used to schedule the writing of the data writing command.

In an embodiment of the present invention, the data access unit updates the cache data correspondence table according to a logical address corresponding to the written data and a physical address of the written data stored in the cache unit.

In an embodiment of the present invention, the data access unit queries the cache data correspondence table according to the logical address corresponding to the written data, so as to obtain the physical address of the written data stored in the cache unit.

In an embodiment of the present invention, when the data access unit receives a data read instruction from the host, the data access unit confirms a read to be read by the data read instruction through the cache data correspondence table. Whether the data is stored in the cache unit. When the read data is stored in the cache unit, the data access unit reads the read data from the cache unit. When the read data is not stored in the cache unit, the data access unit reads the read data from the data storage unit.

In an embodiment of the present invention, when the data access unit replies with the write completion command, the written data in the data write command corresponding to the write complete command has not been written into the data storage unit.

The operation method of the data storage system of the present invention includes the following steps. Receive a data writing command from a host. After a write data of the data write command is stored in a cache unit, a write completion command is returned to the host. Schedule data write commands into a data write schedule. The write data is read from the cache unit and written into a data storage unit according to the data write schedule.

In an embodiment of the present invention, the operation method of the data storage system further includes: after a write data of the data write command is stored in a cache unit, recording a logical address of the write data and the write data Data is stored in a physical address of the cache unit in a cache data table.

In an embodiment of the present invention, the operation method of the data storage system further includes: querying the cache data correspondence table according to a logical address corresponding to the written data to obtain a physical address of the written data stored in the cache unit.

In an embodiment of the present invention, the operation method of the data storage system further includes: receiving a data read command from a host; checking whether a read data to be read by the data read command is stored in the cache data table A cache unit; when the read data is stored in the cache unit, the data access unit reads the read data from the cache unit; and, when the read data is not stored in the cache unit, the data access unit automatically The data storage unit reads out the read data.

Based on the above, in the data storage system and its operation method according to the embodiment of the present invention, the data access unit will reply the write completion command to the host after writing the data and storing it in the cache unit, thereby effectively improving the processing speed of the host , and further improve the data read and write efficiency of the data storage system. Furthermore, the data storage system gradually writes the written data from the cache unit to the data storage unit during background processing, which can greatly reduce the amount of data loss in the data storage system and improve the reliability of data storage in the data storage system.

Description of drawings

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the attached drawings as follows, wherein:

FIG. 1 is a schematic diagram of a data storage system according to an embodiment of the present invention.

FIG. 2 is a flow chart of the operation method of the data storage system according to an embodiment of the invention.

Detailed ways

FIG. 1 is a schematic diagram of a data storage system according to an embodiment of the present invention. Please refer to FIG. 1, in this embodiment, the data storage system 100 includes a data storage unit 110, a cache unit 120, and a data access unit 130, wherein the data storage unit 110 is the main storage unit of the data storage system 100 for storing User data, and when the data storage system 100 is powered off, the stored data in the data storage unit 110 will not disappear. The data storage unit 110 includes, for example, a hard disk and/or a solid state disk, but the embodiment of the present invention is not limited thereto, and the data storage unit 110 may also be a storage device using other data storage technologies. The cache unit 120 is used for temporarily storing user data, wherein the data access speed of the cache unit 120 is higher than that of the data storage unit 110, and when the data storage system 100 is powered off, the stored data in the cache unit 120 will disappear.

In this embodiment, the data access unit 130 is coupled to the data storage unit 110 and the cache unit 120, and the data access unit 130 includes a cache data correspondence table 132 and a data writing schedule table 134, wherein the cache data The correspondence table 132 is used to record the corresponding address information of the write-in data stored in the cache unit 120 , and the data-write schedule table 134 is used to schedule the received data-write commands. The data access unit 130 is used for performing corresponding system operations according to the received data read command or data write command. The above-mentioned system operations include but are not limited to replying to received data writing commands, creating/updating cache data correspondence tables, creating/updating data writing schedules, and ensuring correctness of written data, etc. The operation methods when the data storage system 100 receives the data read command and the data write command will be further described below.

Referring to FIG. 1 , when the data storage system 100 receives a data write command CWR issued by the host 200 , the data storage system 100 stores the written data DW in the data write command CWR in the cache unit 120 . At the same time, when the data access unit 130 receives the data write command CWR, the data access unit 130 will directly reply the write completion command WRD to the host 200, and update the current data write command CWR to the data write queue. schedule 134. When the host 200 receives the write completion command WRD, the host 200 can then send the next command to the data storage system 100 . If the next command issued by the host 200 is still the data write command CWR, the data storage system 100 will first store the written data DW in the cache unit 120 according to the above-mentioned operation process, and the data access unit 130 will directly reply The write completion command WRD is sent to the host 200 , and the current data write command CWR is updated into the data write schedule 134 .

Through the above operation process, the host 200 does not need to actually wait for the data storage system 100 to store the write data DW to the data storage unit 110, so the processing speed of the host 200 can be effectively improved, and the data storage system 100 can further increase the data storage capacity. Read and write efficiency.

Furthermore, the data writing command CWR issued by the host 200 includes not only writing the data DW, but also including the logical address corresponding to the writing data DW. In this embodiment, after the data storage system 100 stores the write data DW in the data write command CWR in the cache unit 120, the data access unit 130 will The physical address of the DW stored in the cache unit 120 is used to create/update the cache data mapping table 132 . In other words, the cache data mapping table 132 is used to record the logical address corresponding to the write data DW in each data write command CWR and the physical address of the write data DW stored in the cache unit 120 .

According to the above, when the data access unit 130 receives the data write command CWR and directly replies the write complete command WRD to the host 200, the data access unit 130 will sequentially arrange the received data write command CWR into the data Write into the schedule table 134 , and sequentially read the write data DW corresponding to the data write command CWR from the cache unit 120 and write into the data storage unit 110 according to the data write schedule table 134 . In an embodiment of the present invention, the write data DW corresponding to each data write command CWR can use the corresponding logical address to query the cache data correspondence table 132 to find out the corresponding write data DW to be stored in the cache The physical address of unit 120. Then, the data access unit 130 can read the corresponding written data DW from the cache unit 120 through the found physical address and write it into the data storage unit 110 .

In the embodiment of the present invention, the data storage system 100 divides the data writing process corresponding to the data writing command CWR into foreground processing and background processing through the data access unit 130 . In the foreground processing, after receiving the data write command CWR, the data storage system 100 first stores the written data DW in the cache unit 120, and before writing the written data DW into the data storage unit 110, directly returns The host 200 writes the completion command WRD to maintain the processing speed and data read/write efficiency between the data storage system 100 and the host 200 . At the same time, in the foreground processing, the data access unit 130 will create a data write schedule table 134 according to the receiving order of the received data write commands CWR, and record the corresponding relevant address information in the cache data corresponding table 132, so that for subsequent background processing.

According to the above, although the data storage system 100 has directly responded to the host 200 with the write completion command WRD during the foreground processing, the written data DW has not actually been written into the data storage unit 110 . In the embodiment of the present invention, the written data DW is written into the data storage unit 110 during background processing. In the background processing, the data storage system 100 will gradually process the previously received data write command CWR according to the data write schedule table 134, and read the corresponding write command CWR from the cache unit 120 through the cache data correspondence table 132. data DW, and write the data DW into the data storage unit 110 . Since the data storage system 100 continues to write the written data DW from the cache unit 120 to the data storage unit 110, when a power failure occurs, although the written data DW in the cache unit 120 will disappear, but due to the cache unit The written data DW in 120 has been written into the data storage unit 110 during background processing, so the data loss of the written data DW can be greatly reduced, so as to improve the data storage reliability of the data storage system 100 .

In the embodiment of the present invention, foreground processing and background processing can be performed simultaneously or interleaved. Furthermore, the operating status of the data storage system 100 may also be considered, such as: busy or idle status, to determine the start timing of the background processing, so as to execute the actual writing of the written data DW without affecting the operating efficiency of the data storage system 100. Background processing of the data storage unit 110 .

In another embodiment of the present invention, the data access unit 130 may perform a data correctness check before writing the write data DW into the data storage unit 110 . In the background processing, the data storage system 100 will gradually process the previously received data write commands CWR according to the data write schedule table 134, because the received data write commands CWR are all sequentially entered into the data write schedule Table 134, and the command content of the data write command CWR received later may include updating the write data of the data write command CWR received earlier, so before writing the write data DW into the data storage unit 110 , the data access unit 130 can first confirm whether the subsequent data write command CWR has updated the earlier data write command CWR in the data write schedule 134, that is, confirms whether the data write command CWR has updated the current data write command CWR. The written data DW is updated, and then it is determined whether to directly read the updated written data DW, and directly write the updated written data DW into the data storage unit 110 . In this way, in addition to ensuring the correctness of the data, the repeated writing time of writing the data DW corresponding to the same logical address can also be saved.

For example, assume that the data storage system 100 successively receives the first data write command CWR1 and the second data write command CWR2, wherein the command content of the first data write command CWR1 includes writing the first data write DW1 into the data The storage unit 110, and the command content of the second data write command CWR2 includes updating the first write data DW1 to the second write data DW2. In the foreground processing, the data access unit 130 stores the first written data DW1 and the second written data DW2 in the cache unit 120 respectively, and records the corresponding relevant address information in the cache data mapping table 132 . Next, the data access unit 130 directly replies to the host 200 with the write completion command WRD, and respectively schedules the first data write command CWR1 and the second data write command CWR2 into the data write schedule 134 .

In the background processing, the data access unit 130 processes the received data write command CWR step by step according to the data write schedule 134 . When processing the first data write command CWR1, the data access unit 130 will confirm whether the subsequent data write command CWR in the data write schedule 134 has updated the first write data DW1, that is, confirm whether There is a data write command CWR corresponding to the same logical address. When the data access unit 130 finds that the instruction content of the second data write command CWR2 includes updating the first write data DW1 to the second write data DW2, the data access unit 130 can ignore the first data write command CWR1 and directly execute the second data writing command CWR2. At this time, the data access unit 130 reads the updated second write data DW2 from the cache unit 120 through the cache data correspondence table 132 and writes it into the data storage unit 110, that is, the second data write command CWR2 replaces the second data write command CWR2. A data write command CWR1, and cancel the original data schedule of the second data write command CWR2. In this way, the correct updated data (second written data DW2) can be directly written in the data storage unit 110, and the writing time of the original written data DW (first written data DW) can be saved, thereby improving the data storage system. 100% reading and writing efficiency and data accuracy.

In the embodiment of the present invention, when the data storage system 100 receives the data read command CRD issued by the host computer 200, the data access unit 130 queries according to the logical address of the read data DR to be read by the data read command CRD The cache data correspondence table 132 is used to confirm whether the read data DR required by the data read command CRD is stored in the cache unit 120 . When the read data DR required by the data read command CRD is stored in the cache unit 120, the data access unit 130 will correspond from the cache data according to the logical address of the read data DR to be read by the data read command CRD. Table 132 finds the physical address of the read data DR stored in the cache unit 120, so as to read the read data DR required by the data read command CRD from the cache unit 120, and directly reply to the data read command CRD. The read data DR. When the read data DR required by the data read command CRD is not stored in the cache unit 120, the data access unit 130 then accesses the data storage unit 110 to read the data stored in the data read command CRD from the data storage unit 110. The required read data DR, and then reply the read data DR required by the data read command CRD.

FIG. 2 is a flow chart of the operation method of the data storage system according to an embodiment of the invention. Please refer to FIG. 2 , in this embodiment, the operation method of the data storage system includes the following steps. First, it is determined whether the host sends a data writing command or a data reading command (step S310). If the host sends a data write command, the data storage system receives the data write command (step S320). Next, the data access unit replies with a write complete command after the data written in the data write command is stored in the cache unit (step S330 ). Next, the data access unit schedules the data write command into the data write schedule (step S340). Next, the data access unit reads out the writing data stored in the cache unit according to the data writing schedule and writes it into the data storage unit (step S350 ).

On the other hand, if the host sends a data read command, the data storage system receives the data read command (step S360). Next, the data access unit confirms whether the read data to be read by the data read command is stored in the cache unit (step S370). When the read data to be read by the data read instruction is stored in the cache unit, that is, the judgment result of step S370 is “Yes”, then the data access unit reads the read data from the cache unit (step S380 ); Conversely, when the read data to be read by the data read instruction is not stored in the cache unit, that is, the judgment result of step S370 is “no”, then the data access unit reads and reads the data from the data storage unit. data (step S390). Wherein, the order of the above steps S310, S320, S330, S340, S350, S360, S370, S380 and S390 is for illustration, and the embodiment of the present invention is not limited thereto. Moreover, details of the above steps S310, S320, S330, S340, S350, S360, S370, S380, and S390 may refer to the embodiment shown in FIG. 1 , and will not be repeated here.

To sum up, in the data storage system and its operation method of the embodiment of the present invention, the data access unit of the data access unit will reply the write completion command to the host after writing the data and storing it in the cache unit, thereby effectively improving the performance of the host. Processing speed, and thus improve the data read and write efficiency of the data storage system. Furthermore, the data storage system gradually writes the written data from the cache unit to the data storage unit during background processing, which can greatly reduce the amount of data loss in the data storage system and improve the reliability of data storage in the data storage system.

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims (10)

1. A data storage system comprising: a data storage unit; a cache unit; and a data access unit, coupled to the data storage unit and the cache unit; Wherein, when the data access unit receives a data write command from a host, the data access unit is used to restore the host after a write data in the data write command is stored in the cache unit a write completion command, scheduling the data write command into a data write schedule, and reading the write data from the cache unit and writing it into the data storage according to the data write schedule unit, Wherein, the data writing schedule includes a writing schedule of a first data writing command, and a writing schedule of at least one second data writing command after the first data writing command, Wherein, when the data access unit executes the write schedule of the first data write command to write a first write data of the first data write command into the data storage unit, it first performs a Data correctness check, wherein the data access unit confirms whether the first data write command is updated in the second data write command, and if so, ignores the first data write command. 2. The data storage system as claimed in claim 1, wherein the data access unit has a cache data correspondence table and the data write schedule table, wherein the cache data correspondence table is used to record the data in the cache unit A corresponding address information of the stored data is stored, and the data writing schedule table is used to schedule the writing of the data writing command. 3. The data storage system according to claim 2, wherein the data access unit updates the cache data corresponding to a logical address corresponding to the write data and a physical address of the write data stored in the cache unit. surface. 4. The data storage system according to claim 3, wherein the data access unit inquires the cache data correspondence table according to the logical address corresponding to the written data to obtain the data stored in the cache unit. The entity address. 5. The data storage system according to claim 1, wherein when the data access unit receives a data read command from the host, the data access unit confirms that the data read command will read Whether the read data is stored in the cache unit. When the read data is stored in the cache unit, the data access unit reads the read data from the cache unit. When the read data is not stored When in the cache unit, the data access unit reads out the read data from the data storage unit. 6. The data storage system according to claim 1, wherein when the data access unit replies to the write completion command, the write data in the data write command corresponding to the write completion command has not been written in the data storage unit. 7. An operation method of a data storage system, comprising: receiving a data write command from a host; After a write data of the data write command is stored in a cache unit, reply a write completion command to the host; scheduling the data write command into a data write schedule; and reading the written data from the cache unit and writing it into a data storage unit according to the data writing schedule, Wherein, the data writing schedule includes a writing schedule of a first data writing command, and a writing schedule of at least one second data writing command after the first data writing command, Wherein, when executing the write schedule of the first data write command to write a first write data of the first data write command into the data storage unit, a data correctness check is performed first, The data correctness checking includes confirming whether the first data writing command is updated in the second data writing command, and if so, ignoring the first data writing command. 8. The operation method of the data storage system as claimed in claim 7, wherein after storing a write data of the data write command in a cache unit, further comprising: A logical address of the written data and a physical address of the written data stored in the cache unit are recorded in a cache data table. 9. The operation method of the data storage system according to claim 8, wherein reading the write data from the cache unit and writing the write data into a data storage unit according to the data write schedule further comprises: The cache data correspondence table is queried according to the logical address corresponding to the write data to obtain the physical address of the write data stored in the cache unit. 10. The operation method of the data storage system as claimed in claim 7, wherein when replying the write completion command, the write data in the data write command corresponding to the write completion command has not been written into the data storage unit.